The present invention relates to a fluid coupler comprising a female coupler and a male coupler, and more particularly to a fluid coupler adapted for use in the transfer of a high pressure fluid.
There is well-known type of fluid coupler in which a female coupler has both a stationary valve member and a movable valve member, and a male coupler has a movable valve member. When the male and female couplers are not connected to each other, their respective valve members function to close their respective fluid passages. Upon insertion of the male coupler into the female coupler, the movable valve member of the female coupler is pushed rearwards by the front end of the male coupler, and the movable valve member of the male coupler is similarly pushed rearwards by the stationary valve member of the female coupler, whereby the fluid passages of the female and male couplers are brought into fluid communication. In such a fluid coupler, when the female and male couplers are not connected to each other, valve members provided in the couplers cover and sealingly engage sealing rings provided on, for example, respective fluid passage walls of the respective couplers so as to prevent fluid leakage. However, a drawback of this arrangement is that when the female and male coupler s are connected to each other the sealing rings are exposed to a high pressure fluid flow passing through the fluid passages, and are therefore liable to be damaged or to become detached. With a view to overcoming this problem, the inventor of the present application has already made an invention which provides a fluid coupler wherein valve members are designed to cover and sealingly engage sealing rings when female and male coupler s are connected to each other, so as to shield the sealing rings from a high pressure fluid flow (refer to Japanese Patent Application H11-153281).
The invention referred to above avoids the problems which occur due to exposure of sealing rings to a high pressure fluid flow. However, in that invention, since the movable valve member of the female coupler has an overall cylindrical configuration and is arranged such that, when the female and male couplers are not connected, the tip end of the movable valve overlaps a small diameter portion of a stepped peripheral surface of the stationary valve member, with the tip end surface thereof being forcibly engaged with the step-connecting upright portion of the stepped peripheral surface of the stationary valve member, if a surge occurs in the pipe line system to which the female coupler is connected, the tip end of the female coupler may be deformed or otherwise damaged. Further, the structure of the fluid coupler is complicated, and is therefore costly and time-consuming to produce.
The object of the present invention is to provide a fluid coupler having a simplified structure in which there are provided in respective female and male couplers valve members designed to shield sealing rings from a high pressure fluid flow when the respective couplers are connected to each other. Further, the present invention aims to provide a fluid coupler in which valve members are designed to prevent deformation or other damage, even in a case that a surge occurs in a pipe line system to which the couplers are connected.
In accordance with the present invention, there is provided a fluid coupler comprising a female coupler and a male coupler, wherein the female coupler comprises:
a cylindrical coupler body having an axis, a front end directed towards the male coupler, a rear end directed away from the male coupler, and interior and exterior surfaces extending between the front and rear ends;
a stationary valve member provided inside and securely connected to the cylindrical coupler body, the stationary valve member having a head positioned at or adjacent the front end of the cylindrical coupler body and a first sealing ring provided on an outer peripheral surface of the head, and,
a cylindrical movable valve member having an axis in parallel with the axis of the cylindrical coupler body, a front end, a rear end, a front end portion extending from the front end towards the rear end, and exterior and interior surfaces extending between the front and rear ends, the cylindrical movable valve member being positioned between the cylindrical coupler body and the stationary valve member and axially movable between:
a closing position wherein the interior surface of the front end portion thereof covers and sealingly engage the first sealing ring of the head, and
an opening position wherein the cylindrical movable valve member has been moved rearwards relative to the stationary valve member and separated from the head, the male coupler comprises:
a cylindrical coupler body having an axis, a front end directed towards the female coupler, a rear end directed away from the female coupler, a front end portion extending from the front end towards the rear end, and exterior and interior surfaces extending between the front and rear ends;
a secondary movable valve member inside the cylindrical coupler body and having a front end, a rear end, a front portion extending from the front end towards the rear end, and an exterior surface;
a cylindrical primary movable valve member having an axis in parallel with the axis of the cylindrical coupler body, a front end, a rear end, a front portion extending from the front end towards the rear end, and exterior and interior surfaces, the cylindrical primary movable valve member being positioned between the secondary movable valve member and the cylindrical coupler body of the male coupler, the exterior surface of the cylindrical primary movable valve member cooperating with the interior surface of the cylindrical coupler body to define a fluid passage of the male coupler; and,
a second sealing ring provided on the interior surface of the front end portion of the cylindrical coupler body of the male coupler;
the secondary movable valve member being movable between:
a forward position at a time when the male coupler has not been inserted into the female coupler, wherein the front end thereof is positioned at or adjacent to the front end of the cylindrical coupler body and
a rearward position at a time when the male coupler has been inserted into the female coupler to establish a fluid connection between the female and male couplers,
the primary movable valve member being movable between:
a forward closing position at the time when the male coupler has not been inserted into the female coupler, wherein the front end portion of the primary movable valve member is positioned between the front end portion of the cylindrical coupler body having the second sealing ring and the front end portion of the secondary movable valve member and sealingly engaged with the second sealing ring; and,
a rearward opening position at the time when the male coupler has been inserted into the female coupler to establish the fluid connection between the female and male couplers; wherein the front end portion of the primary movable valve member is separated rearwards from the front end portion of the cylindrical coupler body having the second sealing ring to define a fluid passage opening between the front end portion of the cylindrical coupler body and the front end portion of the primary movable valve member which opening is fluidly communicated with the fluid passage of the male coupler defined between the interior surface of the cylindrical coupler body and the
exterior surface of the primary movable valve member;
wherein
in an initial stage of insertion of the male coupler into the female coupler, the movable and stationary valve members 5, 15 of the female coupler respectively abut and move the primary and secondary movable valve members of the male coupler rearwards relative to the cylindrical coupler body of the male coupler;
in a second stage of the insertion, the stationary valve member of the female coupler further moves said secondary movable valve member rearwards relative to the primary movable valve member so that the front end portion of the stationary valve member advances into the front end portion of the primary movable valve member and, thus, the interior surface of the front end portion of the primary movable valve member covers and sealingly engages the first sealing ring and, simultaneously, said front end portion of said cylindrical coupler body of said male coupler overlaps said exterior surface of said front end portion of said movable valve member of the female coupler so that the second sealing ring is covered and sealingly engaged by the exterior surface of the movable valve member; and,
in a final stage of the insertion, the movable valve member of the female coupler is moved rearwards by the cylindrical coupler body of the male coupler to the opening position with the second sealing ring being kept engaged by the exterior surface of the movable valve member, and the primary movable member of the male coupler is moved rearwards by the stationary valve member together with the secondary valve member to the rearward opening position while keeping the first sealing ring sealingly engaged by the interior surface of the front end portion of the primary movable valve member.